美国一种新的探空系统——安全探空仪

高空探测系统的最关键方面是探空仪跟踪技术,即提供定位数据和风数据。遗憾的是系统的跟踪部分十分昂贵,且受到环境条件、观测场位置、设备的公差等因素的制约。由于这些原因,直到目前,新的探空系统——安全探空仪的大量工作还只是集中在跟踪技术的设计和试验上。一、目的国家大气研究中心(NCAR)研制安全探空仪系统的最初的目标是提供精度和空间分辨率比以往的方法更高的测风资料,以便使中尺度和区域尺度的研究应用取得令人满意的测量结果。为了同时提高精度和分辨率,需要在系统跟踪性能方面提高约一个量级,并希望在温度和湿度方面有所改进。     

前寒武纪时期地球外层的物理和化学演化的一般特征

对前寒武系不同部分上地壳岩石组合主要特征的分析,可阐明地球岩石圈、水圈、生物圈和大气圈的物理和化学环境演化的许多重要问题。并已得出了某些概念,但新资料,特别是有关地层和地质年代顺序的新资料,现在可允许我们对这些问题作更详细的探讨。太古代太古代的上地壳岩层多半是很特征的。它们不仅在所经历的高级变质作用方面不     

西澳大利亚中央伊尔冈地块花岗岩石的同位素研究

西澳大利亚中央伊尔冈地块所采集花岗岩石的详细Rb-Sr和Pb-Pb全岩同位素研究已用于制定太古宙地壳部分演化的成因模式。在以迪马尔斯-埃文斯顿(DiemalsEvanston)为中心的约4000km~2的地层上进行了研究。花岗岩岩层是复杂的,并包括片麻岩和多种多样变形的(块状到眼状结构)花岗岩侵入体。这些花岗岩体既侵入在花岗岩—片麻岩中,又侵入在绿岩岩层中。在广泛的浅     

7.直接测定铀矿石品位的光中子分析方法

利用光中子源在钻孔中直接测定铀矿石品位的实验研究正在进行中。该方法的原理是利用低能量中子源使钻孔周围岩层中的²³⁵U发生裂变反应,并用快中子探测器记录产生的瞬发裂变中子。由于探测器只记录能量高于源中子初始能量的中子,从而不需要采用脉冲式中子源或调节措施。     

铀和硼分布与变质显微构造的关系——变质流体活动的证据

引言人们早就认识到变质转化时粒间流体的重要,而且在大多数岩石中都有一些流体活动的明显痕迹。然而,流体活动及其在矿物和构造上的分布通过象铀和硼这样非常活泼元素的测定,就能确定。铀和硼是流体的重要成分,而流体是通过交代来源、岩浆来源和渐进变质脱     

Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula

Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.     

西北太平洋上热带风暴和台风转向以后的移速

热带气旋预报员碰到的主要问题之一,就是他必须确定风暴究竟是转向还是继续西移。如果报转向,就必须确定转向点以及预报风暴转向以后的速率和方向。当风暴向东北方向移动时,在48小时的时段内,其平均移速要比转向点上加快2至3倍。由于移速的这种变化,使预报误差急剧增加。     

从空间的相互影响看地理学

一、引言也许人文地理学在理论上的基本贡献可以用地点和位置的概念来概括。地点指局部的基本地域条件,由此可把地理学定义为“人与环境关系”的研究。位置指某一地域的各种影响,更确切地说就是一个区域同另一区域的各种现象的联系。因此,它的研究应该集中在区域之间的关系上,从而引出了象“流通”平“区域间的相互依赖”或者特殊情况下的“分散”与“集中”这些术语。     

Aquaculture-related trace metals in sediments and lobsters and relevance to environmental monitoring program ratings for near-field effects

The study was undertaken to assess the marine environmental effects from feed and waste associated with aquaculture activities. Metal compositions of sediment, lobster, and feed were used to evaluate the extent of detectable effects at 0 m (under the cage) and 50 m distance. Sediments that were collected under the cages and were characterised as hypoxic or anoxic, showed elevated levels of Cu, Zn, organic carbon, and % <63 microm particles, and low Mn and Fe. At 50 m there was a major reduction in waste chemical impact. Using lobster, a bioindicator species, as a tool for detecting near-field impacts, showed accumulations of high Cu associated with active aquaculture sites. Chemical compositions and metal ratios normalised with organic carbon, were used to assess the sediment conditions associated with environmental monitoring program ratings (EMP--normal, hypoxic, and anoxic). Principal component analysis (PCA) was used to explore chemical data at all sites for differentiating normal, hypoxic and anoxic sediment conditions. Selected variables (Cu, Zn, Fe, Mn, organic carbon, and particles <63 microm) were sufficient for the PCA approach with >90% explainable variance of first two components. The groupings based on PCA and cluster analysis were similar to EMP classifications with some exceptions of mis-identification by EMP. The sediment chemistry components were valid indicators for evaluating marine environmental conditions and for assessing aquaculture operating sites. The developed techniques, using chemical variables in combination with EMP and the statistical approach should be useful to predict the effects of aquaculture practices and the suitability of aquaculture operations.